Histograms of flow cytometric cell cycle. HUVECs treated with GRGES (B, 1 mmol/L) or indicated concentrations of accutin (C-F, 0.1, 0.2, 0.4, and 0.8 μmol/L, respectively) for 18 hours were permeablized, fixed, and stained with PI containing RNase, and the cell cycle stages of cells were analyzed. The region of subG1 represents cells undergoing apoptosis-associated DNA degradation and is expressed as a percentage of event (A₀) with respect to the entire cell cycle. Panel A shows the cell cycle stage of normal HUVECs as control. This is a representative one of three similar experiments.